Planarization of ceramic substrates using porous materials

ABSTRACT

This invention provides a concept of using porous materials on ceramic substrate planarization. This planarized substrate comprises a ceramic substrate, a buffer layer, and a nanostructure layer. The ceramic substrate can enhance the structural strength and surface-mount capability. The buffer layer provides the adhesion between a substrate and a nanostructure layer. Nanostructure layer provides the required surface smoothness of the ceramic substrates for performing thin-film processing techniques and enhancing adhesion for metallization and electronic materials. This layer also provides required properties for integrating electronic such as thermal conductivity, electrical insulation, dielectric, etc.

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] This invention mainly provides a concept of using porous materials on ceramic substrate planarization. This planarized substrate can be applied to the fields of electronic information communication, opto-electronics and display.

[0003] 2. Description of the Prior Art

[0004] It is an important postulation for having a planar surface for the thin-film processes. The high cost is due to two main aspects. The first aspect is due to the high substrate-polishing cost based on either silicon wafer or glass manufacture factory. The second aspect is the high fabrication cost on the flattening technology as a key technology to produce metallized module IC.

[0005] At present, some common smoothing techniques are mechanical polishing, chemical mechanical polishing, chemical etching, high temperature reflow through borophosphosilicate, and spin coating. Thin film's roughness and adherence are often limited after surface treatment at which may additionally complicate the processing and increase the cost. The prior arts are shown as following: Prior Art Focal technique Defect US4944836: A method for VLSI The chemical reagent Chem-mech and ULSI (Ultra-Large used in CMP method polishing (CMP) Semiconductor is expensive and hard method for Integration) offer to be controlled during producing coplanar “global the process. metal/insulator films planarization”. And it is also lack of on a substrate The combination of terminate detecting mechanism polishing system. and chemical reagent Finally, a trace of to flatten silicon contaminant may be wafer. More than observed in polish 94% of rough surface process. as consequence can be planarized by CMP method. Silicon Processing Surface of The spin on glass for the VLS: silicon wafer processing can Basics of Thin Films recovered by a liquid provide only local solution via spin planarization. coating method, after Disadvantage may be heat treatment there- observed for example fore a planar dielectric like the formation of layer can be formed. particles, film crack, A deep gap fill capa- delamination and bility on such surface exhausted can be obtained by out-gassing. SOG method. Solid State Technology: A layer of low glass Both B₂H₆ and PH₃ Viscous ehavior of transition temperature are chemically toxic Phosphosilicate, materials BPSG and are employed in Borophosphosilicate deposition on a surface BPSG processing. and Germano- by CVD method. At This planarization can phosphosilicate high temperature be applied to the Glasses in VLSI reflow BPSG on the planarizing dielectric Processing. substrate and then barrier layer before resulting surface metallization. After planarization. the coverage of Al metal layer however BPSG reflowing process cannot be applied. Solid State Excess thick layer of Only a partial Technology: SiO₂ deposited. The planarization can be Chemical Etching application of obtained by chemical anisotropic-etch etching method. It is method can then etch not applicable. back SiO₂ layer to desired thickness.

SUMMARY OF THE INVENTION

[0006] Conclusively, the main purpose of this invention can solve the above-mentioned defects (film crack, delamination, etc.). In order to overcome these problems, this invention provides a concept of using porous materials on ceramic substrate planarization, wherein the nanostructure layer provides the required surface smoothness upon the ceramic substrates and enhances the adhesion between substrate and subsequent thin-film layers.

[0007] This invention can tremendously reduce the production cost due to its simple production process.

[0008] In order to achieve the said objectives, the invention provides a method of using porous materials on ceramic substrate planarization. This invention sustains a surface flattening method by employing the participation of porous materials such as zeolites, zeolite-like, mesoporous and mesoporous composites. Meanwhile, this invention results in good affinity for the electrical and dielectric properties, for instance, thermal conductivity, electrical insulation, dielectric and other required properties for integrated components. Due to a good polarization obtained, this invention permits furthermore an intensive binding between thin films and electronic materials.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1: Schematic drawing of the architecture of the smoothing technology indicated in the invention description.

[0010]FIG. 2: X-ray photograph of example 1.

[0011]FIG. 3: SEM photograph of example 1.

[0012]FIG. 4: Flatten result on the ceramic substrates surface.

[0013]FIG. 5a: Adhesive test of example after deposited an Al film with a thickness of 6.5 μm and platternized by photolithography.

[0014]FIG. 5b: Optical picture of the flatten sample deposited an Al film with a thickness of 6.5 μm.

[0015]FIG. 6a: A current-voltage relationship of the diode which made from the flatten sample (first example).

[0016]FIG. 6b: RLCD integrated circuit made from the flatten sample(first example).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] This invention mainly provides a method of using porous materials on ceramic substrate planarization. The concept of this invention includes at least a layer of ceramic substrate 30, a buffer layer 20, and nanostructured layer 10. As shown in FIG. 1, it is a schematic drawing of the architecture of the smoothing technology indicated in the invention description. First this invention provides a ceramic substrate 30, then a buffer layer 20 forms on the ceramic substrate 30 and a nanostructure layer 10 forms upon the buffer layer 20.

[0018] The ceramic substrate 30 provides the structure stress and surface-mount capability. The buffer layer 20 provides the adhesion between the substrate layer 30 and nanostructured layer 10. The buffer layer 20 can be chosen from one of or some of the following materials: graze, glass, ceramic, mesoporous and mesoporous composites. The nanostructure layer 10 is formed by the self repetitively assembled mechanism in order to offer the required surface smoothness of the ceramic substrates for performing the thin-film process techniques, adhesion for metallization and electronic materials, thermal conductivity, electrical insulation, dielectric and other electric material required functions. The nanostructure layer 10 is chosen from one of or some of the following materials: zeolites, zeolite-like, mesoporous and mesoporous composites. Moreover, the buffer layer 20 and nanostructure layer 10 can be either the same layer or multiplayer.

[0019] The concept of the this invention utilizes the nanostructure layer 10 to provide required thermal conductivity, electrical insulation, adhesion, dielectric and other electric material required functions for the substrate that comprises LTCC, chip-carrier, passive device, active device, light emitting device, optical passive device and optical active device and their complexes.

[0020] The properties and the advantages of this invention are shown in the following example, which can be one of applications.

FIRST EXAMPLE Flatness Test

[0021] The formation of sample as represented in FIG. 2, where substrate 30 was aluminum oxide, buffer layer 20 was glaze, and nanostructure layer 10 was zeolite-like material. X-ray analysis of crystal structure is shown in FIG. 3, the peak signal informs the self-assembly zeolite-like structure. The SEM picture given in FIG. 4 shows the profile of Al203 substrate of 30, glaze buffer layer 20 and nanostructure zeolite-like layer 10. The flatness measurement shown in FIG. 5 shows flatness in angstrom dimension.

SECOND EXAMPLE Adhesion Test

[0022] As shown in FIG. 6a, it is the adhesive test of example 1 after deposited 6.5 μm thickness layers of Al film and platternized by photolithography. FIG. 5b is the optical picture of flatten sample deposited 6.5 μm thickness layers of Al film for adhesion test. A 6.5 μm thickness layer of Al film deposited on flatten sample and platternized by photolithography, this picture indicates an excellent adhesion between substrate and Al layer. It is fully agreement to the α-step profiling measurement shown in FIG. 5a.

THIRD EXAMPLE Practicable Test

[0023] As shown in FIG. 6a, it is the current-voltage relationship of the diode made from the flatten sample (first example), and in FIG. 6b, it is the RLCD integrated circuit made from the flatten sample (first example). Hence, these are evident examples that proof this invention is practicable.

[0024] It should be apparent to those skilled in the art that the above description is only illustrative of specific embodiments and examples of the invention. The invention should therefore cover various modifications and variations made to the herein-described structure and operations of the invention, provided they fall within the scope of the invention as defined in the following appended claims. 

What is claimed is:
 1. A method of using porous materials on ceramic substrate planarization is described as following: provides a ceramic substrate 30, forms a buffer layer 20 on the ceramic substrate 30, and forms a nanostructure layer 10 on the buffer layer 20 to provide the required surface smoothness of the ceramic substrates and adhesion for metallization and electronic materials.
 2. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the nanostructure layer 10 is chosen from one of or some of the following materials: zeolites, zeolite-like, mesoporous and mesoporous composites.
 3. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the buffer layer 20 can be chosen from one of or some of the following materials: graze, glass, ceramic, mesoporous and mesoporous composites.
 4. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the buffer layer 20 and nanostructure layer 10 can be either the same layer or multiplayer.
 5. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the concept of the this invention make use of the nanostructure layer 10 to provide required adhesion, thermal conductivity, electrical insulation, dielectric and other electric material required functions for the substrate of passive device (resistor, inductor, capacitor . . . etc.).
 6. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the concept of the this invention make use of the nanostructure layer 10 to provide required adhesion, thermal conductivity, electrical insulation, dielectric and other electric material required functions for the substrate of active device (transistor, diode, memory device . . . etc).
 7. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the concept of the this invention make use of the nanostructure layer 10 to provide required adhesion, thermal conductivity, electrical insulation, dielectric and other electric material required functions for the substrate of light emitting device (laser diode, LED, field emitter . . . etc).
 8. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the concept of the this invention make use of the nanostructure layer 10 to provide required adhesion, thermal conductivity, electrical insulation, dielectric and other electric material required functions for the substrate of optical passive device (wave guide, photo detector . . . etc.).
 9. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the concept of the this invention make use of the nanostructure layer 10 to provide required adhesion, thermal conductivity, electrical insulation, dielectric and other electric material required functions for the substrate of optical active device (optical amplifier, optical switches, optical regulator . . . etc).
 10. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the nanostructure layer 10 can be applied to the substrate for passive device, active device, light emitting device, optical passive device, optical active device, and theirs complex.
 11. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the concept of the this invention make use of the nanostructure layer 10 to provide required thermal conductivity, electrical insulation, adhesion, dielectric and other electric material required functions for the substrate of chip-carrier, and the said chip-carrier integrated with one of or some of the passive device, active device, light emitting device, optical passive device or optical active device.
 12. A method of using porous materials on ceramic substrate planarization of claim 1, wherein the concept of the this invention make use of the nanostructure layer 10 to provide required thermal conductivity, electrical insulation, adhesion, dielectric and other electric material required functions for the substrate of LTCC, and the said LTCC integrated with one of or some of the passive device, active device, light emitting device, optical passive device, optical active device or chip-carrier. 